, 1887-09-18
THE THEORY OF STORMS.
An Easily Understood Description
How They Originate and Pass AWAY.

@N1 Df~tTlDIlOn OF
How They Originate and Pass Away.
Sergt. E. B. Dunn, the signal service
officer in charge of the station on the
Equitable building, thus explained the
theory of storms the other day:
Storms are caused" he said, first
by the meeting and commingEing of in
equal atmospheric temperatures or pres
sures; second, by the rotation of the
earth, and, thirdly, by unequal specific
gravity of different layers of air. The
first of these causes is the prime one; the
other two are but of secondary and COM
~paratively slight Importance in the gen.
Grafton of a storm.
at is a well known fact that warm air
rises. 1t is equally well known that the
earth becomes heated by the suns rays
falling upon it, and by the absorption and
radiation of this stored up heat renders
the temperature higher at the surface
than at elevated points. For a time this
hot air on the surface is kept down by
atmospheric pressure, but there comes a
time when the expansion becomes SO
great as to break through the cold air
pressure, n the hot air goes up with a
rush, rising sometimes to great height.
AS this warm air rises it creates a>vacuum
below, and the cooler air rushes in from
all sides to fill its place. This cool air, as
it gets gradually heated, also rises, and
more cool air rushes in to again fill the
Right at this point where the
hot air first rises is the center of a storm.
h vacuum caused by the ascending hot
air sucks into its vortex the air from
every point of the compass, and this sue
ton causes wind, but places affected by
q storm thus formed, it will be seen, will
have the wind from different points of
the compass, according to their direc-
ton from tLe storm center. Thus, a
locality directly south of a storm center
will nave the wind from the south, as it
rushes north. When this warm air has
accumulated at q sufficiently high alti-
tude, and become surrounded by a cooler
air, the moisture in it begins to condense,
forming rain.
1.-The rushing in of the cool air to fill
the vacuum caused by the rising hot air
gives motion to the accumulation of
warm air, and it begins to whirl about
iii a circle, but at the center all is calm
and clear. Thus it is that sometimes we
experience "a hull in the Storm as il is
called. Such a brief respite is nothing
more than the passing of a storm cente
directly over head, through which the
Dull 6Ntu may Billie uIlODoITuCIeulys
"As this storm keeps whirling about
over head it continues to gather energy,
and grows by the accession of more heated
air, exactly as a SNOWFALL is increased in
diameter by rolling it in the snow. AT
last the accumulation becomes of such
proportions as to feel the effects of the
earth's rotation, and it begins to move.
This rotation of the earth, being from
yynat tn aaGt riuaa oil tho otnrp,g pf nn-
extent the same general direction. Such
general direction, however, from west to
east, is liable to reflections from various
causes, such as mountains, conditions of
the atmosphere, by coming in contact
with other storms or air currents, and
by large areas of water.
mine out of ten American storms
originate in the mountainous regions of
the northwest, where the warm air of
the valleys rises and comes in contact
with the cool air from the great eleva-
tons of the Rocky mountains. These
storms take a generally southeasterly di-
rection until they get into the dry regions
of Kansas, and there, becoming fam
ished, as it were, for want of moisture,
and as if seeming the water for which
they long from the direction of the great
lake region, they make a turn to the
northeast and proceed to the great lakes,
where they absorb abundance of moisture,
and then travel m east, deluging us with
this water from the lakes. All such zen
eral storms pass out from this country to
the Atlantic, through the st. Lawrence
valley. Within recent years these Ameri-
can storms have been actually traced
across the Atlantic to Europe, and some
of them even as far as Asia.
"All storms originate in the same way,
whether on land or at sea; in summer or
In winter. The u~ndercurrent of air
which rises need not necessarily be warm
to make it rise; as, for instance, where
the temperature is below the freezing
point; but the un~dercurrent must be of
a higher temperature than that above
and surrounding it to force it to rise. In
other words, q storm is originated by a
c~ommingling of unequal atmospheric
Temperatures. New York Commercial
Advertiser.